Idler pulleys or deflecting pulleys of traction mechanism drives are intended for ensuring a defined prestress of the traction mechanism and as slip-free a belt drive as possible. Idler pulleys or deflecting pulleys of this type are consequently also designated as a deflection unit.
In internal combustion engines, traction mechanisms as toothed belts for the drive of camshafts or as V-belt for the drive of secondary assemblies are known. Idler or deflecting pulleys or deflection units form important elements of these traction mechanisms. One object of these components is to ensure a minimum looping of the traction mechanism on the belt pulleys in order to achieve as slip-free a drive as possible. Furthermore, deflecting elements are used in order to provide a defined traction mechanism drive layout, with the result that the traction mechanism can be guided according to a contour defined by the design of the internal combustion engine.
DE 100 43 840 A1 discloses a deflecting pulley or idler pulley composed of a rolling bearing, in the inner ring of which is inserted a threaded fastener for fastening purposes which, furthermore, is guided through a spacer sleeve determining an axial distance of the deflecting pulley from a housing of the internal combustion engine. The rolling bearing is surrounded on the outside by a running disk which is produced from plastic and which may also be designated as a running roller. The running disk is fastened positively to an outer ring of the rolling bearing via a hub. In the installed state of the deflecting or idler pulley, the traction mechanism of the traction mechanism is guided on the running disk.
Furthermore, idler pulleys for traction mechanisms are known, in which setting is carried out by means of a rotational displacement of the idler pulley axis of rotation about a pivot axis introduced within the outside diameter of the idler pulley.